The present invention pertains to systems for transferring precise amounts of fluid solutions at high speeds, and more particularly to means for coupling two or more of such systems together. Such systems are especially useful for the compounding of hyperalimentation solutions.
As background information, hyperalimentation therapy is the intravenous feeding of, for example, a protein-carbohydrate mixture to a patient. It is used primarily to meet the patient's protein and caloric requirements which are unable to be satisfied by oral feeding. The protein may be in the form of free-amino acids or protein hydrolysate and the carbohydrate, commonly is dextrose. In addition to the protein and carbohydrate, vitamins (water-soluble and fat-soluble) and electrolytes also can be supplied in this therapy.
Each of these parenteral ingredients and the combination thereof are particularly susceptible to the growth of deleterious organisms and it is desirable that they be administered to the patient in a sterile condition. Thus, because these protein and carbohydrate solutions cannot be pre-compounded by the manufacturer, but must be combined at the time of their use, their compounding must be performed under sterile conditions to avoid organism growth.
U.S. Pat. No. 4,513,796 to Miller et al. describes a bulk compounding system in which multiple solutions are transferred from separate sources to a single container. The system includes a controller that surveys various process conditions and warrants of any failure of those conditions. Each source of solution is in fluid communication with the container through independent flexible tubing. Fluid flow through the tubing is controlled by multiple peristaltic pumps.
It has been known in the past that to ensure sterility during the compounding of hyperalimentation solutions, compounding should be performed under a laminar flow hood. Laminar flow hoods are used for reducing the risk of airborre contamination of such solutions. These units operate by taking room air and passing it through a pre-filter to remove gross contaminates, such as dust and lint. The air is then compressed and channeled through a bacterial retentive filter in the hood in a laminar flow fashion. The purified air flows out over the entire work surface of the hood in parallel lines at a uniform velocity. The bacterial retentive type of filter is designed to remove all bacteria from the air being filtered.
Compounding under a laminar flow hood aids in preventing airborne contamination, but it is relatively cumbersome and expensive and would not be useful for eliminating any other source of contamination, such as contamination caused by handling. When using a hood, the operator may inadvertently perform the work at the end or outside of the hood and not within the recommended space, at least six (6) inches within the hood, which insures the benefits of the air being purified. Time must be taken and care must be exercised to maintain a direct open path between the filter and the compounding area. Solution bottles and other non-sterile objects cannot be placed at the back of the hood work area next to the filter because these objects could contaminate everything downstream and disrupt the laminar flow pattern of the purified air. Also, in using a laminar flow hood, it is necessary routinely to clean the work surface of the hood before any compounding is performed.
As can be seen from the above discussion, it is very important that any equipment designed to be used under a laminar flow hood does not disrupt the laminar flow of air across the equipment at any location on the equipment which is important to keep sterile. For example, in the situation in which hyperalimentation solutions are compounded under a laminar flow hood, any connectors between the solution source bags and the container to be filled with hyperalimentation solution must be carefully designed so that laminar flow at the connection points is maintained. A particularly critical junction with respect to bulk compounding systems for producing hyperalimentation solution is the junction between the container to be filled and a manifold which receives all the tubing from the source containers. The present invention takes into consideration this need for maintaining laminar flow across such a junction and, in addition, provides a relatively simple means of combining two or more bulk compounders of the type described in U.S. Pat. No. 4,513,796 together to enable a user-to compound a wider variety of solutions.